Quality Assessment of Sub-base Highway Pavement Materials in Lagelu Local Government Area, Ibadan, Oyo State, Nigeria

Abstract

Road development quality delivery in West Africa mostly depends on the quality of available sub-base pavement materials within economic distance. This paper thus aimed at assessing the quality of sub-base road pavement material in Lagelu Local Government Area of Ibadan, South-Western, Nigeria. Soil samples were collected from four different locations at depths ranging from 0.5m to 1.0m. Samples were subjected to Natural moisture content, Specific gravity, Grain size analysis, Atterberg limits, Compaction and California bearing ratio laboratory tests. The sieve analysis results indicate that the fine grain content varying from 16.80 % and 30.70 %. The soil samples are well graded ranging from coarse to clay particle sizes. The compaction test results revealed the maximum dry density range from 2.25 Mg/m3 to 2.28 Mg/m3 and optimum moisture content of between 7.1 % and 7.3 %. The materials were classified after AASHTO soil classification system as A-1-b with California Bearing Ratio (CBR) test results ranging from 74% to 76%. The variation in the values depends on the moisture content and the density of the materials. It was observed that the values were well within the permissible specification by the Federal Ministry of Works General Specifications of the country, rated as excellent to good sub-base materials.